Generally, an organic optoelectric device is a device requiring alternating current of charges between an electrode and an organic matter using holes or electrons.
An organic optoelectric device may be classified into a type in which excitons are formed in an organic layer by photons introduced to the device from an external light source according to an operation principle, and then separated into electrons and holes, and each of these electrons and holes is transferred to other electrode, and used as a current source (voltage source), and a type in which voltage or current is applied to two or more electrodes to inject holes or electrons into an organic semiconductor forming an interface with the electrodes, and operation is performed by the injected electrons or holes.
As an example of the organic optoelectric device, an organic photoelectric device, an organic light-emitting device, an organic solar cell, an organic photoconductor drum, an organic transistor and the like are mentioned, and all of these require an injection or transport material of holes, an injection or transport material of electrons, or a luminescent material for driving the device.
Among these, the organic solar cell is composed of a joint structure of the materials of a hole acceptor and an electron acceptor, and when visible light is absorbed, electron-hole pairs are produced in the hole acceptor, and electrons are transferred to the electron acceptor, so that the electron-hole is separated, and thus, by this process, a photovoltaic effect is shown.
In particular, since an organic thin film solar cell using a high molecule has merits of a low unit cost of production and allowing a freely bendable, flexible device to have a large area, as compared with an inorganic solar cell using silicone, a lot of researches on this are in progress, as in Patent Document 1.
Meanwhile, as a representative material used in a photo-conversion active layer of an organic thin film solar cell, poly(3-hexylthiophene) (P3HT) may be mentioned, and it was reported that when it was manufactured into a device with a C60 fullerene derivative having a high electron affinity, efficiency of about 4-5% was shown.
However, P3HT has demerits such as a light absorption region being limited, and thus, in order to overcome these demerits and manufacture a highly efficient organic thin film solar cell, there is a demand for development of a novel high molecule having a low band gap of a large light absorption region, excellent hole mobility, and an appropriate molecular level.